UV Radiation- energy that is emitted in the form of electromagnetic waves with a wavelength of 1-380nm, which is composed of UV-A, UV-B, and UV-C light; UV-A light being the longest wavelength and having the smallest energy and UV-C light being the shortest wavelength and having the highest energy. All UV-C light and most UV-B light is filtered out of the atmosphere via the ozone layer. However, UV-A light travels to the surface of the earth.
[Environmental Pollution; v88n2; 219; 1995.]
[Photochemistry and Photobiology; v51n6; 757; 1990.] 
Atmospheric Chemistry Glossary

Electromagnetic radiation at wavelengths shorter than the violet end of visible light (5 to 300 nm); the atmosphere of the Earth effectively blocks the transmission of most ultraviolet light.